Human stem cells

Technique developed to
reprogram adult stem cells

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DRAFT VERSION; BEING EXPANDED

Types of stem cells:

Recapping information in this section of stem cells:

Embryonic stem cells are pluripotent. That is, they have
the potential of developing into any of the 220 cell types in the
human body (e.g. blood cells, heart cells, brain cells, muscle cells, bone
cells, etc). Unfortunately, they can only be obtained from embryos. This
causes very serious ethical problems among those who believe that human life
becomes a human person at conception. This concern has slowed embryonic stem
cell research to a crawl in most western countries with the exception of the
UK.

Adult stem cells: These can be harvested from newborns, children
and adults with very few ethical concerns. However, they have already started
to specialize and thus do not have the same level of flexibility as do
embryonic stem cells. They can only be coaxed into replicating a narrow
range of cell types.

In late 2007, a technique was proven in principle that can reprogram adult
stem cells so that they have many of the same
properties and potential of embryonic stem cells. This may completely
revolutionize future research techniques, allow government research funding to
be increased, and offer hope to the approximately 100 million Americans who
suffer from a wide range of debilitating diseases and disorders that may
eventually be treated or cured with stem cells.

Reprogramming techniques developed:

In 2007-JUN, a medical research group led by Dr. Shinya Yamanaka of Kyoto
University in Japan announced a new technique that reprogrammed adult skin cells
taken from mice so that they exhibit many of the properties of embryonic stem
cells. They found four genetic factors that reprogrammed the mouse cells in to
"Induced Pluripotent Stem (iPS) cells. Their technique involves:

Harvesting a living cell from the skin of a mouse.

Implanting four genes into a retrovirus.

Injecting the retrovirus into the skin cell where it copies its RNA genome
into the DNA of the mouse cell's chromosomes.
1

The four genes reprogram the skin cell to act in many ways like embryonic
stem cells.

Two research teams announced publicly on 2007-NOV-21 that the technique has
been replicated using human skin cells. Dr. Yamanaka's group reprogrammed skin
sells taken from the face of a 36-year-old woman; their article appeared in
Cell magazine. The other was a team led by Junying Yu, working with James
Thomson of the University of Wisconsin who used cells from the amputated
foreskin of a newborn; their paper appeared in Science magazine.

The technique is in its earliest stages of development. However, it may
eventually result in treatments and cures for a wide range of disorders and
diseases. It may allow the creation of:

Nerve cells to repair spinal court injuries and cure paralysis.

Blood cells and bone marrow to treat leukemia.

Pancreatic cells to cure diabetes.

Brain cells to treat Parkinson's and Alzheimer's patients.

Heart cells to repair cardiac muscles

Liver cells to regenerate livers damaged by cirrhosis and other
diseases.

etc.

The technique may revolutionize:

Organ and tissue transplants by allowing the generation of entire
replacement organs without any possibility of rejection by the body,

Research into human genetic defects,

Cancer research,

Screening new drugs for toxicity in advance of human trials,

etc.

Only embryonic stem cells had earlier offered such promise; however they were
plagued with ethical concerns. They also presented practical problems, like the
difficulty of obtaining a sufficient number of embryos for large-scale
treatment.

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Reactions:

Dr. Janet Rossant chief of research at Toronto's Hospital for Sick
Children and deputy scientific director of the Canadian Stem Cell Network
said:

"It's really quite remarkable. ... This is early days, this is proof
of principle, but I think this is very encouraging that these cells are
being reprogrammed into a state that has many of the properties of an
embryonic stem cell. ......these two studies show, relatively
conclusively, that at least in principle, ... you can take adult human
cells ... and just by adding the right genes making a change in gene
expression patterns, you can turn them into cells that, at least in
culture, resemble human embryonic stem cells." 2

"Dr. Yamanaka's work is monumental in its importance to the field of
stem cell science and its potential impact on our ability to accelerate
the benefits of this technology to the bedside. Not only does this
discovery enable more research, it offers a new pathway to apply the
benefits of stem cells to human disease."

Concerns:

The technique involves the injection of four genes into an adult cell that
disrupts the cell's DNA. This may cause cancer. Dr. Rossant noted that the cells
cannot be used in their current state for patient treatment. She said:

"We don't know how exactly to control the expression of these genes. It's
not clear that these cells would be used for treating patients at this
point. ... I feel that this area is moving very fast. There is a lot of
potential for understanding biology of disease with this kind of approach.
..."

Political aspects:

President Bush's team is claiming some of the credit for the development of
this technique. On 2007-NOV-20, Karl Zinsmeister, the chief domestic
policy adviser to President Bush, said in an interview:

"If you set reasonable parameters and offer a lot of encouragement and
public funding, science will solve this dilemma, and you don't have to have
a culture war about this." 3

Dr James Thomson, said the restrictions placed on embryonic stem cell
research may have slowed discovery of the new technique, since scientists needed
to study embryonic cells first before they could figure out how to do the same
thing without using embryos. He said:

"My feeling is that the political controversy set the field back four or
five years." 3

That represents a great deal of suffering and loss of life among the tens of
millions of Americans if their future treatments and cures are thus delayed.
3

Some suggest that because of the uncertainties
related to this new technique, that attempts should continue to release
embryonic stem cell research from its current federal funding restrictions.

Rep. Diana DeGette (D-CO) said:

"I don't think this changes the debate. We still need to encourage
all types of research, and we need to put ethical oversight in place."
3

"While this is exciting basic research, it could still take years to
get this to work in humans in a way that could be used clinically. I
cannot overstate that this is early-stage research and that we should
not abandon other areas of stem cell research." 3

Sen. Edward M. Kennedy (D-MA) described the new developments as "extraordinary
scientific breakthroughs. " However, he said that embryonic stem cell
research must continue.

"Instead of aiding that fight, the Bush administration is hampering
it through needless restrictions on stem cell research and by denying
NIH the funds it needs to capitalize on new advances" 3

Anti-Bush comments from readers of the Washington
Post article 3 are rather brutal.4

References used:

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